This works around JACK not allowing to directly access physical
input buffers by creating an explicit connection.
Ardour access input-buffers directly without connection
for input meters and AFL. This work in general since data
on those ports are always read unconditionally at the start of
each process cycle.
jack_port_get_buffer (jack_port_by_name (c, "system:capture_1"), n);
However with jack this fails if the given port is not connected.
Due to an internal jack optimization collecting input data is
skipped for ports that have no connections.
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